A keyset or chorded keyboard is a computer input device that allows the user to enter characters or commands formed by pressing several keys together, like playing a "chord" on a piano. The large number of combinations available from a small number of keys allows text or commands to be entered with one hand, leaving the other hand free. A secondary advantage is that it can be built into a device that is too small to contain a normal-sized keyboard.
An ergonomic chorded keyboard without the board is known as a keyer.
Stenograph first model, Miles Bartholomew, 1879
Hall-Braille writer, model 1, 1892
A braille keyboard
In computing, an input device is a piece of equipment used to provide data and control signals to an information processing system, such as a computer or information appliance. Examples of input devices include keyboards, computer mice, scanners, cameras, joysticks, and microphones.
Ergonomic keyboard
Chorded keyboard
Thumb keyboard
Keyer